Planetary gear train of an automatic transmission for a vehicle

ABSTRACT

A planetary gear train of an automatic transmission for a vehicle includes input and output shafts, and first, second, third, fourth, and fifth planetary gear sets, each including three rotational elements. The gear train also includes nine shafts for selectively connecting the planetary gear sets, the input and output shafts, and a transmission housing in various configurations to achieve at least ten forward speeds and at least one reverse speed.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to and the benefit of Korean PatentApplication No. 10-2017-0143289 filed in the Korean IntellectualProperty Office on Oct. 31, 2017, the entire contents of which areincorporated herein by reference.

BACKGROUND (a) Field of the Disclosure

The present disclosure relates to an automatic transmission for avehicle.

(b) Description of the Related Art

Research into realizing more shift-stages of an automatic transmissionhas been undertaken to achieve enhancement of fuel consumption andimprove drivability. Increased oil prices have triggered fiercecompetition to enhance vehicle fuel consumption.

Therefore, research in the field of engines has been undertaken toachieve weight reduction and to enhance fuel consumption by so-calleddownsizing. Research in the field of automatic transmissions has alsobeen performed to simultaneously provide better drivability and fuelconsumption by achieving more shift stages.

In order to achieve more shift stages for an automatic transmission, thenumber of parts is typically increased, which may deteriorateinstallability, production cost, weight and/or power flow efficiency.

Recently, eight-speed automatic transmissions have been introduced.Planetary gear trains for automatic transmissions enabling more shiftstages are under investigation.

Conventional automatic transmissions of eight or more shift-stagestypically include three to four planetary gear sets and five to sevenengagement elements (frictional elements). The transmission may easilybecome lengthy, thereby deteriorating installability.

In this regard, disposing planetary gear sets in parallel or employingdog clutches instead of wet-type control elements have been attempted.However, such arrangements may not be widely applicable. Using dogclutches may easily deteriorate shift-feel.

The above information disclosed in this Background section is only toenhance understanding of the background of the disclosure. Therefore,the background may contain information that is not prior art that isalready known in this country to a person of ordinary skill in the art.

SUMMARY

The present disclosure relates to a planetary gear train of an automatictransmission for a vehicle enabling at least ten forward speeds, therebyproviding better performance and fuel efficiency of a vehicle.

A planetary gear train of an automatic transmission for a vehicle mayinclude an input shaft for receiving an input torque, an output shaftfor outputting a shifted torque, a first planetary gear set havingfirst, second, and third rotational elements, a second planetary gearset having fourth, fifth, and sixth rotational elements, a thirdplanetary gear set having seventh, eighth, and ninth rotationalelements, a fourth planetary gear set having tenth, eleventh, andtwelfth rotational elements, a fifth planetary gear set havingthirteenth, fourteenth, and fifteenth rotational elements, a first shaftfixedly connected with the second rotational element and fixedlyconnected with the input shaft, a second shaft fixedly connected withthe fourteenth rotational element and fixedly connected with the outputshaft, a third shaft fixedly connected with the third rotational elementand the fifth rotational element, a fourth shaft fixedly connected withthe sixth rotational element and the tenth rotational element, a fifthshaft fixedly connected with the eighth rotational element, the eleventhrotational element, and the fifteenth rotational element, a sixth shaftfixedly connected with the twelfth rotational element, and a pluralityof shafts, each of which is selectively connected to the transmissionhousing and fixedly connected to a rotational element of the first,second, third, and fifth planetary gear sets that is not fixedlyconnected with any of the first to sixth shafts.

The plurality of shafts may include a seventh shaft fixedly connectedwith the first rotational element, the fourth rotational element, andthe seventh rotational element and selectively connected with thetransmission housing, an eighth shaft fixedly connected with the ninthrotational element and selectively connected with the transmissionhousing, and a ninth shaft fixedly connected with the thirteenthrotational element and selectively connected with the transmissionhousing. The second shaft and the third shaft, the fourth shaft and thefifth shaft, and the sixth shaft and the ninth shaft may be selectivelyconnected with each other, respectively.

The planetary gear train may further include three clutches and threebrakes. Each clutch may be selectively connected with a correspondingpair among the input shaft, the output shaft, and the first to ninthshafts. Each brake may be selectively connected with the seventh shaft,the eighth shaft, and the ninth shaft to the transmission housing,respectively.

The three clutches may include a first clutch arranged between thesecond shaft and the third shaft, a second clutch arranged between thefourth shaft and the fifth shaft, and a third clutch arranged betweenthe sixth shaft and the ninth shaft. The three brakes may include afirst brake arranged between the seventh shaft and the transmissionhousing, a second brake arranged between the eighth shaft and thetransmission housing, and a third brake arranged between the ninth shaftand the transmission housing.

The plurality of shafts may include a seventh shaft fixedly connectedwith the first rotational element and the fourth rotational element andthe seventh rotational element and selectively connected with thetransmission housing, an eighth shaft fixedly connected with the ninthrotational element and selectively connected with the transmissionhousing, and a ninth shaft fixedly connected with the thirteenthrotational element and selectively connected with the transmissionhousing. The second shaft and the third shaft, the fifth shaft and thesixth shaft, and the sixth shaft and the ninth shaft may be selectivelyconnected with each other, respectively.

The planetary gear train may further include three clutches and threebrakes. Each clutch may be selectively connected with a correspondingpair among the input shaft, the output shaft, and the first to ninthshafts. Each brake may be selectively connected with the seventh shaft,the eighth shaft, and the ninth shaft to the transmission housing,respectively.

The three clutches may include a first clutch arranged between thesecond shaft and the third shaft, a second clutch arranged between thefifth shaft and the sixth shaft, and a third clutch arranged between thesixth shaft and the ninth shaft. The three brakes may include a firstbrake arranged between the seventh shaft and the transmission housing, asecond brake arranged between the eighth shaft and the transmissionhousing, and a third brake arranged between the ninth shaft and thetransmission housing.

The first planetary gear set may be a single pinion planetary gear sethaving a first sun gear, a first planet carrier, and a first ring gearas the first, second, and third rotational elements, respectively. Thesecond planetary gear set may be a single pinion planetary gear sethaving a second sun gear, a second planet carrier, and a second ringgear as the fourth, fifth, and sixth rotational elements, respectively.The third planetary gear set may be a single pinion planetary gear sethaving a third sun gear, a third planet carrier, and a third ring gearas the seventh, eighth, and ninth rotational elements, respectively. Thefourth planetary gear set may be a single pinion planetary gear sethaving a fourth sun gear, a fourth planet carrier, and a fourth ringgear as the tenth, eleventh, and twelfth rotational elements,respectively. The fifth planetary gear set may be a single pinionplanetary gear set having a fifth sun gear, a fifth planet carrier, anda fifth ring gear as the thirteenth, fourteenth, and fifteenthrotational elements, respectively.

A planetary gear train according to an embodiment of the presentdisclosure may realize ten forward speeds and one reverse speed byoperating five planetary gear sets by controlling six engagementelements.

A planetary gear train according to an embodiment of the presentdisclosure realizes shifting by controlling five planetary gear sets bysix engagement elements, achieves uniform torque load over clutches andbrakes, and minimizes torque load applied to the respective shaft'sconnection with the rotational elements, thereby enhancing durabilityand efficiency.

In addition, a minimal number of engagement elements are controlled torealize shifting between shift-stages of ten forward speeds and onereverse speed. Accordingly, reduction of clutch drag, enhancement oftorque transmission efficiency, and enhancement of flexibility of outputgear ratios are achieved, thereby enhancing linearity of step ratios.

In addition, a gear ratio span may be increased to above 9.0 whilerealizing ten forward speeds and one reverse speed, thereby maximizingengine power performance and fuel economy.

In addition, a planetary gear train according to an embodiment of thepresent disclosure may substantially improve driving stability byrealizing shift-stages appropriate for rotational speed of an engine dueto the multi-stages of an automatic transmission.

Further, effects that can be obtained or expected from embodiments ofthe present disclosure are directly or suggestively described in thefollowing detailed description. In other words, various effects expectedfrom embodiments of the present disclosure are described in thefollowing detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of a planetary gear train according to afirst embodiment of the present disclosure.

FIG. 2 is an operational chart for respective control elements atrespective shift-stages applicable to a planetary gear train accordingto a first embodiment of the present disclosure.

FIG. 3 is a schematic diagram of a planetary gear train according to asecond embodiment of the present disclosure.

DETAILED DESCRIPTION OF THE EMBODIMENTS

It is desired to develop a planetary gear train having advantages ofrealizing, by minimal complexity, at least ten forward speeds and atleast one reverse speed. In this aspect, the present disclosure relatesto a planetary gear train of an automatic transmission for a vehicle.The disclosed planetary gear train may improve power deliveryperformance and fuel consumption of an engine by using a smaller numberof parts and by increasing a gear ratio span. The disclosed planetarygear train may also achieve linearity of shift stage step ratios.

Hereinafter, an embodiment of the present disclosure will be describedin detail with reference to the drawings. In the drawings, the followingsymbols are used to identify various elements of the disclosedembodiments, wherein:

-   -   i. B1, B2, B3 represent first, second, and third brakes;    -   ii. C1, C2, C3 represent first, second, and third clutches;    -   iii. PG1, PG2, PG3, PG4, PG5 represent first, second, third,        fourth, and fifth planetary gear sets;    -   iv. S1, S2, S3, S4, S5 represent first, second, third, fourth,        and fifth sun gears;    -   v. PC1, PC2, PC3, PC4, PC5 represent first, second, third,        fourth, and fifth planet carriers;    -   vi. R1, R2, R3, R4, R5 represent first, second, third, fourth,        and fifth ring gears;    -   vii. P1, P2, P3, P4, and P5 represent first, second, third,        fourth, and fifth pinion gears;    -   viii. IS represents an input shaft;    -   ix. OS represents an output shaft;    -   x. TM1, TM2, TM3, TM4, TMS, TM6, TM7, TM8, TM9 represent first,        second, third, fourth, fifth, sixth, seventh, eighth, and ninth        shafts.

The drawings and description are to be regarded as illustrative innature and not restrictive. Like reference numerals designate likeelements throughout the specification.

In the following description, using names or terms to identifycomponents such as first, second, third, and the like is todifferentiate the names because the names of the components areotherwise the same as each other. Such a naming convention is notintended to denote or set an order thereof, and the disclosure is notintended to be so limited.

FIG. 1 is a schematic diagram of a planetary gear train according to afirst embodiment of the present disclosure.

Referring to FIG. 1, a planetary gear train according to a firstembodiment of the present disclosure includes first, second, third,fourth, and fifth planetary gear sets PG1, PG2, PG3, PG4, and PG5arranged on a same axis. The planetary gear train also includes an inputshaft IS, an output shaft OS, nine shafts TM1-TM9 interconnectingrotational elements of the first, second, third, fourth, and fifthplanetary gear sets PG1, PG2, PG3, PG4, and PG5, engagement elements ofthree clutches C1-C3 and three brakes B1-B3, and a transmission housingH.

Torque input from the input shaft IS is shifted by cooperative operationof the first, second, third, fourth, and fifth planetary gear sets PG1,PG2, PG3, PG4, and PG5 and output through the output shaft OS.

In this embodiment of the present disclosure, the planetary gear setsare arranged in the order of the first, second, third, fourth, and fifthplanetary gear sets PG1, PG2, PG3, PG4, and PG5, from an engine side.

The input shaft IS is an input member. The input shaft IS may receive atorque from a crankshaft of an engine through a torque converter.

The output shaft OS is an output member. The output shaft OS is arrangedon the same axis as the input shaft IS and outputs a shifted drivingtorque to a driveshaft through a differential apparatus.

In this embodiment, the first planetary gear set PG1 is a single pinionplanetary gear set. The first planetary gear set PG1 includes a firstsun gear 51, a first planet carrier PC1 rotatably supporting a pluralityof first pinion gears P1 externally gear-meshed with the first sun gearS1, and a first ring gear R1 internally gear-meshed with the pluralityof first pinion gears P1. The first sun gear S1 acts as a firstrotational element N1, the first planet carrier PC1 acts as a secondrotational element N2, and the first ring gear R1 acts as a thirdrotational element N3.

In this embodiment, the second planetary gear set PG2 is a single pinionplanetary gear set. The second planetary gear set PG2 includes a secondsun gear S2, a second planet carrier PC2 rotatably supporting aplurality of second pinion gears P2 externally gear-meshed with thesecond sun gear S2, and a second ring gear R2 internally gear-meshedwith the plurality of second pinion gears P2. The second sun gear S2acts as a fourth rotational element N4, the second planet carrier PC2acts as a fifth rotational element N5, and the second ring gear R2 actsas a sixth rotational element N6.

In this embodiment, the third planetary gear set PG3 is a single pinionplanetary gear set. The third planetary gear set PG3 includes a thirdsun gear S3, a third planet carrier PC3 rotatably supporting a pluralityof third pinion gears P3 externally gear-meshed with the third sun gearS3, and a third ring gear R3 internally gear-meshed with the pluralityof third pinion gears P3. The third sun gear S3 acts as a seventhrotational element N7, the third planet carrier PC3 acts as an eighthrotational element N8, and the third ring gear R3 acts as a ninthrotational element N9.

In this embodiment, the fourth planetary gear set PG4 is a single pinionplanetary gear set. The fourth planetary gear set PG4 includes fourthsun gear S4, a fourth planet carrier PC4 rotatably supporting aplurality of fourth pinion gears P4 externally gear-meshed with thefourth sun gear S4, and a fourth ring gear R4 internally gear-meshedwith the plurality of fourth pinion gears P4. The fourth sun gear actsas a tenth rotational element N10, the fourth planet carrier PC4 acts asan eleventh rotational element N11, and the fourth ring gear R4 acts asa twelfth rotational element N12.

In this embodiment, the fifth planetary gear set PG5 is a single pinionplanetary gear set. The fifth planetary gear set PG5 includes a fifthsun gear S5, a fifth planet carrier PC5 rotatably supporting a pluralityof fifth pinion gears P5 externally gear-meshed with the fifth sun gearS5, and a fifth ring gear R5 internally gear-meshed with the pluralityof fifth pinion gears P5. The fifth sun gear S5 acts as a thirteenthrotational element N13, the fifth planet carrier PC5 acts as afourteenth rotational element N14, and the fifth ring gear R5 acts as afifteenth rotational element N15.

In this embodiment of the arrangement of the first, second, third,fourth, and fifth planetary gear sets PG1, PG2, PG3, PG4, and PG5, thefirst rotational element N1 is fixedly connected with the fourthrotational element N4 and the seventh rotational element N7. The thirdrotational element N3 is fixedly connected with the fifth rotationalelement N5. The sixth rotational element N6 is fixedly connected withthe tenth rotational element N10. The eighth rotational element N8 isfixedly connected with the eleventh rotational element N11 and thefifteenth rotational element N15, thereby forming nine shafts TM1-TM9.

The nine shafts TM1-TM9 are hereinafter described in detail.

In this embodiment, the first shaft TM1 is fixedly connected with thesecond rotational element N2 (first planet carrier PC1) and fixedlyconnected with the input shaft IS, thereby always acting as an inputelement.

The second shaft TM2 is fixedly connected with the fourteenth rotationalelement N14 (fifth planet carrier PC5) and fixedly connected with theoutput shaft OS, thereby always acting as an output element.

The third shaft TM3 is fixedly connected with third rotational elementN3 (first ring gear R1) and the fifth rotational element N5 (secondplanet carrier PC2).

The fourth shaft TM4 is fixedly connected with sixth rotational elementN6 (second ring gear R2) and the tenth rotational element N10 (fourthsun gear S4).

The fifth shaft TM5 fixedly connected with the eighth rotational elementN8 (third planet carrier PC3), the eleventh rotational element N11(fourth planet carrier PC4), and the fifteenth rotational element N15(fifth ring gear R5).

The sixth shaft TM6 is fixedly connected with the twelfth rotationalelement N12 (fourth ring gear R4).

The seventh shaft TM7 fixedly connected with the first rotationalelement N1 (first sun gear S1), the fourth rotational element N4 (secondsun gear S2), and the seventh rotational element N7 (third sun gear S3).

The eighth shaft TM8 is fixedly connected with the ninth rotationalelement N9 (third ring gear R3).

The ninth shaft TM9 is fixedly connected with the thirteenth rotationalelement N13 (fifth sun gear S5).

Each of the nine shafts, TM1-TM9 may be a rotational member that fixedlyinterconnects the input and output shafts and the rotational elements ofthe planetary gear sets PG1, PG2, PG3, PG4, and PGS. Each of the nineshafts may be a rotational member that selectively interconnects arotational element to the transmission housing H. Each of the nineshafts may also be a fixed member fixed to the transmission housing H.

In the disclosure, the fixedly connected members always rotate at a samespeed when two or more members are described to be “fixedly connected”,where each of the members may be any of a shaft, an input shaft, anoutput shaft, a rotational member, and a transmission housing.

When two or more members are described to be “selectively connected” byan engagement element, the selectively connected members rotateseparately when the engagement element is not engaged and rotate at asame speed when the engagement element is engaged. It may be understoodthat in the case that a member is “selectively connected” with atransmission housing by an engagement element, the member may bestationary when the engagement element is engaged.

In this embodiment, the first shaft TM1 is fixedly connected with theinput shaft IS, the second shaft TM2 is selectively connected with thethird shaft TM3, the fourth shaft TM4 is selectively connected with thefifth shaft TMS, and the sixth shaft TM6 is selectively connected withthe ninth shaft TM9.

The seventh shaft TM7, the eighth shaft TM8, and the ninth shaft TM9 areselectively connected with the transmission housing H, therebyselectively acting as a fixed element, respectively.

The engagement elements of three clutches C1, C2, and C3 are arrangedbetween the nine shafts TM1-TM9, the input shaft IS, and the outputshaft OS, thereby forming selective connections.

The nine shafts TM1-TM9 may be selectively connected with thetransmission housing H by control elements of the three brakes B1, B2,and B3.

In this embodiment, the six engagement elements of the three clutchesC1-C3 and the three brakes B1-B3 are arranged as follows.

The first clutch C1 is arranged between the second shaft TM2 and thethird shaft TM3. The first clutch C1 selectively connects the secondshaft TM2 and the third shaft TM3, thereby controlling power deliverytherebetween.

The second clutch C2 is arranged between the fourth shaft TM4 and thefifth shaft TM5. The second clutch C2 selectively connects the fourthshaft TM4 and the fifth shaft TM5, thereby controlling power deliverytherebetween.

The third clutch C3 is arranged between the sixth shaft TM6 and theninth shaft TM9. The third clutch C3 selectively connects the sixthshaft TM6 and the ninth shaft TM9, thereby controlling power deliverytherebetween.

The first brake B1 is arranged between the seventh shaft TM7 and thetransmission housing H. The first brake B1 selectively connects theseventh shaft TM7 to the transmission housing H.

The second brake B2 is arranged between the eighth shaft TM8 and thetransmission housing H. The second brake B2 selectively connects theeighth shaft TM8 to the transmission housing H.

The third brake B3 is arranged between the ninth shaft TM9 and thetransmission housing H. The third brake B3 selectively connects theninth shaft TM9 to the transmission housing H.

In this embodiment, the engagement elements of the first, second, andthird clutches C1, C2, and C3 and the first, second, and third brakesB1, B2, and B3 may be realized as multi-plate hydraulic pressurefriction devices that are frictionally engaged by hydraulic pressure.However, it should not be understood to be limited thereto, sincevarious other configurations that are electrically controllable may beavailable.

FIG. 2 is an operational chart for the respective control elements atrespective shift-stages applicable to a planetary gear train accordingto a first embodiment of the present disclosure.

Referring to FIG. 2, a planetary gear train according to a firstembodiment of the present disclosure realizes shifting between tenforward speeds and one reverse speed by operating three elements amongthe engagement elements of the first, second, and third clutches C1, C2,and C3 and the first, second, and third brakes B1, B2, and B3.

In this embodiment, the third clutch C3 and the second and third brakesB2 and B3 are simultaneously operated in the forward first speed D1.

As a result, the first shaft TM1 always receives an input torque bybeing fixedly connected with the input shaft IS, and the sixth shaft TM6is connected with the ninth shaft TM9 by the operation of the thirdclutch C3.

In addition, the eighth and ninth shafts TM8 and TM9 respectively act asfixed elements by the operation of the second and third brakes B2 andB3, thereby realizing the forward first speed and outputting a shiftedtorque to the output shaft OS connected with the second shaft TM2.

In this embodiment, the second clutch C2 and the second and third brakesB2 and B3 are simultaneously operated in the forward second speed D2.

As a result, the first shaft TM1 always receives an input torque bybeing fixedly connected with the input shaft IS, and the fourth shaftTM4 is connected with the fifth shaft TM5 by the operation of the secondclutch C2.

In addition, the eighth and ninth shafts TM8 and TM9 respectively act asfixed elements by the operation of the second and third brakes B2 andB3, thereby realizing the forward second speed and outputting a shiftedtorque to the output shaft OS connected with the second shaft TM2.

In this embodiment, the first clutch C1 and the second and third brakesB2 and B3 are simultaneously operated in the forward third speed D3.

As a result, the first shaft TM1 always receives an input torque bybeing fixedly connected with the input shaft IS, and the second shaftTM2 is connected with the third shaft TM3 by the operation of the firstclutch C1.

In addition, the eighth and ninth shafts TM8 and TM9 respectively act asfixed elements by the operation of the second and third brakes B2 andB3, thereby realizing the forward third speed and outputting a shiftedtorque to the output shaft OS connected with the second shaft TM2.

In this embodiment, the first and third clutches C1 and C3 and thesecond brake B2 are simultaneously operated in the forward fourth speedD4.

As a result, the first shaft TM1 always receives an input torque bybeing fixedly connected with the input shaft IS, the second shaft TM2 isconnected with the third shaft TM3 by the operation of the first clutchC1, and the sixth shaft TM6 is connected with the ninth shaft TM9 by theoperation of the third clutch C3.

In addition, the eighth shaft TM8 acts as a fixed element by theoperation of the second brake B2, thereby realizing the forward fourthspeed and outputting a shifted torque to the output shaft OS connectedwith the second shaft TM2.

In this embodiment, the first and second clutch C1 and C2 and the secondbrake B2 are simultaneously operated in the forward fifth speed D5.

As a result, the first shaft TM1 always receives an input torque bybeing fixedly connected with the input shaft IS, the second shaft TM2 isconnected with the third shaft TM3 by the operation of the first clutchC1, and the fourth shaft TM4 is connected with the fifth shaft TM5 bythe operation of the second clutch C2.

In addition, the eighth shaft TM8 acts as a fixed element by theoperation of the second brake B2, thereby realizing the forward fifthspeed and outputting a shifted torque to the output shaft OS connectedwith the second shaft TM2.

In this embodiment, the first, second, and third clutches C1, C2, and C3are simultaneously operated in the forward sixth speed D6.

As a result, the first shaft TM1 always receives an input torque bybeing fixedly connected with the input shaft IS, the second shaft TM2 isconnected with the third shaft TM3 by the operation of the first clutchC1, the fourth shaft TM4 is connected with the fifth shaft TM5 by theoperation of the second clutch C2, and the sixth shaft TM6 is connectedwith the ninth shaft TM9 by the operation of the third clutch C3.

Accordingly, the first, second, third, fourth, and fifth planetary gearsets PG1, PG2, PG3, PG4, and PG5 integrally rotate, thereby realizingthe sixth speed where a torque is output as inputted and outputting ashifted torque to the output shaft OS connected with the second shaftTM2.

In this embodiment, the first and second clutch C1 and C2 and the thirdbrake B3 are simultaneously operated in the forward seventh speed D7.

As a result, the first shaft TM1 always receives an input torque bybeing fixedly connected with the input shaft IS, the second shaft TM2 isconnected with the third shaft TM3 by the operation of the first clutchC1, and the fourth shaft TM4 is connected with the fifth shaft TM5 bythe operation of the second clutch C2.

In addition, the ninth shaft TM9 acts as a fixed element by theoperation of the third brake B3, thereby realizing the forward seventhspeed and outputting a shifted torque to the output shaft OS connectedwith the second shaft TM2.

In this embodiment, the first and second clutch C1 and C2 and the firstbrake B1 are simultaneously operated in the forward eighth speed D8.

As a result, the first shaft TM1 always receives an input torque bybeing fixedly connected with the input shaft IS, the second shaft TM2 isconnected with the third shaft TM3 by the operation of the first clutchC1, and the fourth shaft TM4 is connected with the fifth shaft TM5 bythe operation of the second clutch C2.

In addition, the seventh shaft TM7 acts as a fixed element by theoperation of the first brake B1, thereby realizing the forward eighthspeed and outputting a shifted torque to the output shaft OS connectedwith the second shaft TM2.

In this embodiment, the second clutch C2 and the first and third brakesB1 and B3 are simultaneously operated in the forward ninth speed D9.

As a result, the first shaft TM1 always receives an input torque bybeing fixedly connected with the input shaft IS, and the fourth shaftTM4 is connected with the fifth shaft TM5 by the operation of the secondclutch C2.

In addition, the seventh and ninth shafts TM7 and TM9 act as fixedelements by the operation of the first and third brakes B1 and B3,thereby realizing the forward ninth speed and outputting a shiftedtorque to the output shaft OS connected with the second shaft TM2.

In this embodiment, the first and second clutch C1 and C2 and the firstbrake B1 are simultaneously operated in the forward tenth speed D10.

As a result, the first shaft TM1 always receives an input torque bybeing fixedly connected with the input shaft IS, the fourth shaft TM4 isconnected with the fifth shaft TM5 by the operation of the second clutchC2, and the sixth shaft TM6 is connected with the ninth shaft TM9 by theoperation of the third clutch C3.

In addition, the seventh shaft TM7 acts as a fixed element by theoperation of the first brake B1, thereby realizing the forward tenthspeed and outputting a shifted torque to the output shaft OS connectedwith the second shaft TM2.

In the reverse speed REV, the third clutch C3 and the first and secondbrakes B1 and B2 are simultaneously operated.

As a result, the first shaft TM1 always receives an input torque bybeing fixedly connected with the input shaft IS, and the sixth shaft TM6is connected with the ninth shaft TM9 by the operation of the thirdclutch C3.

In addition, the seventh and eighth shafts TM7 and TM8 act as fixedelements by the operation of the first and second brakes B1 and B2,thereby realizing the reverse speed and outputting a shifted torque tothe output shaft OS connected with the second shaft TM2.

FIG. 3 is a schematic diagram of a planetary gear train according to asecond embodiment of the present disclosure.

According to a planetary gear train according to a first embodiment ofthe present disclosure shown in FIG. 1, the second clutch C2 forintegrally rotating the fourth planetary gear set PG4 is arranged toselectively connect the fourth shaft TM4 and the fifth shaft TM5.However, according to a planetary gear train according to a secondembodiment of the present disclosure shown in FIG. 3, the second clutchC2 is arranged to selectively connect the fifth shaft TM5 and the sixthshaft TM6.

Although the planetary gear train according to a second embodimentdiffers from a planetary gear train according to a first embodiment inthe location of the second clutch C2, operations and functions of theplanetary gear train remains the same.

As described above, a planetary gear train according to an embodiment ofthe present disclosure may realize ten forward speeds and one reversespeed by operating five planetary gear sets PG1, PG2, PG3, PG4, and PG5by controlling three clutches C1, C2, and C3 and three brakes B1, B2,and B3.

A planetary gear train according to an embodiment of the presentdisclosure realizes shifting by controlling five planetary gear setsPG1, PG2, PG3, PG4, and PG5 by six engagement elements C1, C2, C3, B1,B2, and B3, achieves uniform torque load over clutches and brakes, andminimizes torque load applied to the respective shaft's connection withrotational elements, thereby enhancing durability and efficiency.

In addition, a minimal number of engagement elements are controlled torealize shifting between shift-stages of ten forward speeds and onereverse speed. Accordingly, reduction of clutch drag, enhancement oftorque transmission efficiency, and enhancement of flexibility of outputgear ratios are achieved, thereby enhancing linearity of step ratios.

In addition, a gear ratio span may be increased to above 9.0 whilerealizing ten forward speeds and one reverse speed, thereby maximizingengine power performance and fuel economy.

In addition, a large number of shift-stages are realized. Accordingly,an engine speed may be maintained at a low speed by enabling an optimalshift-stage, thereby improving N.V.H. characteristics of a vehicle.

While this disclosure has been described in connection with what ispresently considered to be practical embodiments, it is to be understoodthat the disclosure is not limited to the disclosed embodiments, but, onthe contrary, is intended to cover various modifications and equivalentarrangements included within the spirit and scope of the appendedclaims.

What is claimed is:
 1. A planetary gear train of an automatictransmission for a vehicle, comprising: an input shaft for receiving aninput torque; an output shaft for outputting a shifted torque; a firstplanetary gear set having a first, a second, and a third rotationalelement; a second planetary gear set having a fourth, a fifth, and asixth rotational element; a third planetary gear set having a seventh,an eighth, and a ninth rotational element; a fourth planetary gear sethaving a tenth, an eleventh, and a twelfth rotational element; a fifthplanetary gear set having a thirteenth, a fourteenth, and a fifteenthrotational element; a first shaft fixedly connected with the secondrotational element and fixedly connected with the input shaft; a secondshaft fixedly connected with the fourteenth rotational element andfixedly connected with the output shaft; a third shaft fixedly connectedwith the third rotational element and the fifth rotational element; afourth shaft fixedly connected with the sixth rotational element and thetenth rotational element; a fifth shaft fixedly connected with theeighth rotational element, the eleventh rotational element, and thefifteenth rotational element; a sixth shaft fixedly connected with thetwelfth rotational element; and a plurality of shafts, each of which isselectively connected to a transmission housing and fixedly connected toa rotational element of the first, second, third, and fifth planetarygear sets that is not fixedly connected with any of the first to sixthshafts.
 2. The planetary gear train of claim 1, wherein the plurality ofshafts comprises: a seventh shaft fixedly connected with the firstrotational element, the fourth rotational element, and the seventhrotational element and selectively connected with the transmissionhousing; an eighth shaft fixedly connected with the ninth rotationalelement and selectively connected with the transmission housing; and aninth shaft fixedly connected with the thirteenth rotational element andselectively connected with the transmission housing, wherein the secondshaft and the third shaft, the fourth shaft and the fifth shaft, and thesixth shaft and the ninth shaft are selectively connected with eachother, respectively.
 3. The planetary gear train of claim 2, furthercomprising: three clutches each selectively connecting a correspondingpair among the input shaft, the output shaft, and the first to ninthshafts; and three brakes each selectively connecting the seventh shaft,the eighth shaft, and the ninth shaft to the transmission housing,respectively.
 4. The planetary gear train of claim 3, wherein the threeclutches comprise: a first clutch arranged between the second shaft andthe third shaft; a second clutch arranged between the fourth shaft andthe fifth shaft; and a third clutch arranged between the sixth shaft andthe ninth shaft, and the three brakes comprise: a first brake arrangedbetween the seventh shaft and the transmission housing; a second brakearranged between the eighth shaft and the transmission housing; and athird brake arranged between the ninth shaft and the transmissionhousing.
 5. The planetary gear train of claim 1, wherein the pluralityof shafts comprises: a seventh shaft fixedly connected with the firstrotational element, the fourth rotational element, and the seventhrotational element and selectively connected with the transmissionhousing; an eighth shaft fixedly connected with the ninth rotationalelement and selectively connected with the transmission housing; and aninth shaft fixedly connected with the thirteenth rotational element andselectively connected with the transmission housing, wherein the secondshaft and the third shaft, the fifth shaft and the sixth shaft, and thesixth shaft and the ninth shaft are selectively connected with eachother, respectively.
 6. The planetary gear train of claim 5, furthercomprising: three clutches each selectively connecting a correspondingpair among the input shaft, the output shaft, and the first to ninthshafts; and three brakes each selectively connecting the seventh shaft,the eighth shaft, and the ninth shaft to the transmission housing,respectively.
 7. The planetary gear train of claim 6, wherein the threeclutches comprise: a first clutch arranged between the second shaft andthe third shaft; a second clutch arranged between the fifth shaft andthe sixth shaft; and a third clutch arranged between the sixth shaft andthe ninth shaft, and the three brakes comprise: a first brake arrangedbetween the seventh shaft and the transmission housing; a second brakearranged between the eighth shaft and the transmission housing; and athird brake arranged between the ninth shaft and the transmissionhousing.
 8. The planetary gear train of claim 1, wherein: the firstplanetary gear set is a single pinion planetary gear set having a firstsun gear, a first planet carrier, and a first ring gear as the first,second, and third rotational elements, respectively; the secondplanetary gear set is a single pinion planetary gear set having a secondsun gear, a second planet carrier, and a second ring gear as the fourth,fifth, and sixth rotational elements, respectively; the third planetarygear set is a single pinion planetary gear set having a third sun gear,a third planet carrier, and a third ring gear as the seventh, eighth,and ninth rotational elements, respectively; the fourth planetary gearset is a single pinion planetary gear set having a fourth sun gear, afourth planet carrier, and a fourth ring gear as the tenth, eleventh,and twelfth rotational elements, respectively; and the fifth planetarygear set is a single pinion planetary gear set having a fifth sun gear,a fifth planet carrier, and a fifth ring gear as the thirteenth,fourteenth, and fifteenth rotational elements, respectively.
 9. Aplanetary gear train of an automatic transmission for a vehicle,comprising: an input shaft for receiving an input torque; an outputshaft for outputting a shifted torque; a first planetary gear set havinga first, a second, and a third rotational element; a second planetarygear set having a fourth, a fifth, and a sixth rotational element; athird planetary gear set having a seventh, an eighth, and a ninthrotational element; a fourth planetary gear set having a tenth, aneleventh, and a twelfth rotational element; a fifth planetary gear sethaving a thirteenth, a fourteenth, and a fifteenth rotational element,wherein the first rotational element is fixedly connected with thefourth rotational element and the seventh rotational element andselectively connected with a transmission housing, the second rotationalelement is fixedly connected with the input shaft, the third rotationalelement is fixedly connected with the fifth rotational element, thesixth rotational element is fixedly connected with the tenth rotationalelement, the eighth rotational element is fixedly connected with theeleventh rotational element and the fifteenth rotational element andselectively connected with the tenth rotational element, the ninthrotational element is selectively connected with the transmissionhousing, the thirteenth rotational element is selectively connected withthe twelfth rotational element and selectively connected with thetransmission housing, the fourteenth rotational element is fixedlyconnected with the output shaft and selectively connected with the thirdrotational element.
 10. The planetary gear train of claim 9, furthercomprising: three clutches each selectively connecting a correspondingpair of the rotational elements; and three brakes each selectivelyconnecting the first rotational element, the ninth rotational element,and the thirteenth rotational element to the transmission housing,respectively.
 11. The planetary gear train of claim 10, wherein thethree clutches comprise: a first clutch arranged between the thirdrotational element and the fourteenth rotational element; a secondclutch arranged between the tenth rotational element and the eleventhrotational element; and a third clutch arranged between the twelfthrotational element and the thirteenth rotational element, and the threebrakes comprise: a first brake arranged between the first rotationalelement and the transmission housing; a second brake arranged betweenthe ninth rotational element and the transmission housing; and a thirdbrake arranged between the thirteenth rotational element and thetransmission housing.
 12. The planetary gear train of claim 9, wherein:the first planetary gear set is a single pinion planetary gear sethaving a first sun gear, a first planet carrier, and a first ring gearas the first, second, and third rotational elements, respectively; thesecond planetary gear set is a single pinion planetary gear set having asecond sun gear, a second planet carrier, and a second ring gear as thefourth, fifth, and sixth rotational elements, respectively; the thirdplanetary gear set is a single pinion planetary gear set having a thirdsun gear, a third planet carrier, and a third ring gear as the seventh,eighth, and ninth rotational elements, respectively; the fourthplanetary gear set is a single pinion planetary gear set having a fourthsun gear, a fourth planet carrier, and a fourth ring gear as the tenth,eleventh, and twelfth rotational elements, respectively; and the fifthplanetary gear set is a single pinion planetary gear set having a fifthsun gear, a fifth planet carrier, and a fifth ring gear as thethirteenth, fourteenth, and fifteenth rotational elements, respectively.13. A planetary gear train of an automatic transmission for a vehicle,comprising: an input shaft for receiving an input torque; an outputshaft for outputting a shifted torque; a first planetary gear set havinga first, a second, and a third rotational element; a second planetarygear set having a fourth, a fifth, and a sixth rotational element; athird planetary gear set having a seventh, an eighth, and a ninthrotational element; a fourth planetary gear set having a tenth, aneleventh, and a twelfth rotational element; a fifth planetary gear sethaving a thirteenth, a fourteenth, and a fifteenth rotational element,wherein the first rotational element is fixedly connected with thefourth rotational element and the seventh rotational element andselectively connected with a transmission housing, the second rotationalelement is fixedly connected with the input shaft, the third rotationalelement is fixedly connected with the fifth rotational element, thesixth rotational element is fixedly connected with the tenth rotationalelement, the eighth rotational element is fixedly connected with theeleventh rotational element and the fifteenth rotational element andselectively connected with the twelfth rotational element, the ninthrotational element is selectively connected with the transmissionhousing, the thirteenth rotational element is selectively connected withthe twelfth rotational element and selectively connected with thetransmission housing, the fourteenth rotational element is fixedlyconnected with the output shaft and selectively connected with the thirdrotational element.
 14. The planetary gear train of claim 13, furthercomprising: three clutches each selectively connecting a correspondingpair of the rotational elements; and three brakes each selectivelyconnecting the first rotational element, the ninth rotational element,and the thirteenth rotational element to the transmission housing,respectively.
 15. The planetary gear train of claim 14, wherein thethree clutches comprise: a first clutch arranged between the thirdrotational element and the fourteenth rotational element; a secondclutch arranged between the twelfth rotational element and the eleventhrotational element; and a third clutch arranged between the twelfthrotational element and the thirteenth rotational element, and the threebrakes comprise: a first brake arranged between the first rotationalelement and the transmission housing; a second brake arranged betweenthe ninth rotational element and the transmission housing; and a thirdbrake arranged between the thirteenth rotational element and thetransmission housing.
 16. The planetary gear train of claim 13, wherein:the first planetary gear set is a single pinion planetary gear sethaving a first sun gear, a first planet carrier, and a first ring gearas the first, second, and third rotational elements, respectively; thesecond planetary gear set is a single pinion planetary gear set having asecond sun gear, a second planet carrier, and a second ring gear as thefourth, fifth, and sixth rotational elements, respectively; the thirdplanetary gear set is a single pinion planetary gear set having a thirdsun gear, a third planet carrier, and a third ring gear as the seventh,eighth, and ninth rotational elements, respectively; the fourthplanetary gear set is a single pinion planetary gear set having a fourthsun gear, a fourth planet carrier, and a fourth ring gear as the tenth,eleventh, and twelfth rotational elements, respectively; and the fifthplanetary gear set is a single pinion planetary gear set having a fifthsun gear, a fifth planet carrier, and a fifth ring gear as thethirteenth, fourteenth, and fifteenth rotational elements, respectively.